Question

In the figure shown below, the charge on the left plate of the $10\mu F$ capacitor is $-30\mu C$. The charge on the right plate of the $6\mu F$ capacitor is _______$\mu C$.

Answer 1

Answer: 18

Let $q_1$ and $q_2$ be charge on $6\mu F$ and $4\mu F$ respectively.
$q_1+q_2=q$ .....(i)
Also, $\frac{q_1}{C_1}=\frac{q_2}{C_2}$....(ii)
$\dots .[\because C_1$ and $C_2$ are in parallel combination]
$\Rightarrow q_2=\frac{C_2}{C_1}{q}_1$
$=\frac{4}{6}{q}_1$
Using (i) and (ii),
$\frac{10}{6}{q}_1=q$
$\therefore q=\frac{5}{3}{q}_1$
$\Rightarrow q_1=\frac{3}{5}\times 30=18\mu C$